Williams' Felipe Massa set the fastest time at Bahrain so far this year on the penultimate day of testing as Red Bull's gremlins returned to restrict world champion Sebastian Vettel to just one lap.

In truth Vettel only made it as far as Turn Four before pulling to the side of the track with a problem. He took a good look at the rear of the car before it was trucked back to the pits and returned to the garage. About 30 minutes later the team tried sending him out again, but this time Vettel only made it as far as the end of the pit lane before stopping. In the afternoon he put his race suit back on as work continued in the garage, but the team discovered a mechanical issue, leaving him with just one day left in the car on Sunday before the start of the season.

Vettel has completed just 85 laps so far over the three weeks of testing, a total surpassed in one day by six of the other drivers on track on Saturday. The only driver who had an equally frustrating day was Adrian Sutil, whose Sauber returned to the pits from its installation lap with flames coming from the rear and failed to return to the circuit later in the day.

At the top of the timesheets the three fastest laps were set in the final hour of the day, with Daniil Kvyat briefly putting the Toro Rosso in first place before Felipe Massa set a decent lap with with a 1:34.450 and then improved with a blistering 1:33.258. It was 0.025s quicker than Nico Rosberg's best time last week and quicker than the Mercedes on the day by 0.226s. It backs up the pace shown by Williams over longer runs last week and marks them out as a serious contender heading into the opening races of the season. Kimi Raikkonen was roughly two seconds slower than the two Mercedes-powered cars and after a slow morning of just nine laps, he completed 81 by the end of the day.

Kevin Magnussen was fourth fastest after spending much of the afternoon on top. He was scheduled to complete a race simulation in the afternoon and by the chequered flag had 85 laps to his name. The race sim appeared to be interrupted by Romain Grosjean who stopped on track and caused a red flag with an MGU-K issue. Unfortunately for the Lotus driver, it proved to be the end of his day and he had to settle for just 33 laps after also losing time with a different electrical issue in the morning.

After struggling at times this week, Marcus Ericsson and Caterham led the lap count with 117 by the chequered flag, just ahead of Nico Hulkenberg who completed a healthy 115.